1. Field of the Invention
This invention relates to pipelines and more particularly to methods for the inspection of pipelines.
2. Background of the Art
Pipelines are widely used in a variety of industries, allowing a large amount of material to be transported from one place to another. A variety of fluids, such as oil and/or gas, as well as particulate, and other small solids suspended in fluids, are transported cheaply and efficiently using underground pipelines. Pipelines can be subterranean, submarine, on the surface of the earth, and even suspended above the earth. Subterranean and submarine pipelines especially carry enormous quantities of oil and gas products indispensable to energy-related industries, often under tremendous pressure and at high temperature and at high flow rates.
Unfortunately, even buried pipelines are not completely protected from the elements. Corrosion of a pipeline can cause small spots of weakness, which if not detected and fixed, could result in a pipeline catastrophe. Subsidence of the soil, local construction projects, seismic activity, weather, and simply wear and tear from the friction of fluids passing through a pipeline can lead to defects and anomalies in the pipeline. Shifts in the pipeline location can also lead to defects, cracks, leaks, bumps, and other anomalies, within the interior of the pipeline.
Both the internal and external surface of a pipeline can be damaged by environmental factors such as the reactivity of the material flowing through the pipeline, the pressure, temperature and chemical characteristics of various products and contaminants inside and outside the pipeline, corrosion, mechanical damage, fatigue, crack, stress, corrosion cracks, hydrogen induced cracks, distortion due to dents or wrinkles, exposure, and damage to weight coating and free spanning of offshore pipelines. Moreover, submarine pipelines face a hostile environment of ships anchors, troll boards and seabed scouring due to strong currents. Although timely repair or maintenance of pipelines can lengthen the service lifetime of the pipeline, a rupture or serious leak (also referred to as failure) within the pipeline can be difficult and expensive to repair and can be difficult to locate.
The cost to industry as well as the potential for damages to human life from a pipeline failure can be great. A pipeline can be adversely affected by the anomalies that may lead to failure long before a failure occurs. Consequently, industry has produced various inspection devices for detecting defects and anomalies. For example, it is known to use a pipeline inspection apparatus that includes a vehicle capable of moving along the interior of the pipe by the flow of fluid through the pipe to inspect the pipe for location of anomalies. Such prior inspection vehicles or “pigs” have typically included various means of urging the pigs along the interior of the pipe including rubber seals, tractor treads, and even spring-loaded wheels. In the case of the latter, the pigs have further included odometers that count the number of rotations of the wheels. Various measurements have been made with pigs using wipers or even the wheels of pigs having wheels. The wipers or wheels of pigs have included devices such as ultrasound receivers, odometers, calipers, and other electrical devices for making measurements. For example, a has been used to record shape of the pipeline according to the ultrasonic signature received by ultrasonic transducers, each data sample associated with an odometer measurement.
Other related pipeline inspection technologies have included the use of measurement devices such as ultrasonic transducers mounted on an inspection unit within the pig that emit high frequency sound and measure and record the reflected and refracted signals from the walls of the pipe. However, the use of pigs, while well known and generally dependable, is not without its problems. For example, a pig, depending upon its purpose, can significantly reduce the flow of materials through a pipeline while the pig is present therein. Even more undesirable is the possibility that a pipeline has become so narrowed or blocked that a pig can be lost within a pipeline and require a reverse flush of the pipeline, or even more drastic measures, to retrieve it. In some applications, a pipeline must be shutdown completely during pigging operations. Most pipelines are privately operated and any loss in production, including loss of production due to downtime for pigging operations, can be costly.
The present invention provides systems and methods wherein discrete microflowable devices are utilized to measure and record pipeline parameters of interest relating to the pipeline systems.